Created sample format for a JSON city file

Translated settings for Boulder into external JSON format. Next
step will be to read these settings in the Python script using
the json package.

PS Also snuck in a .gitignore to handle vim swap files

Author: vanderwb

.gitignore

@@ -0,0 +1,2 @@
+# Don't bother with vim swp files
+*.swp

cities/boulder.json

@@ -0,0 +1,17 @@
+{ "city": {
+    "name":     "Boulder",
+    "state":    "CO",
+    "high":     {
+        "avg":  18.5,
+        "std":  4.5
+    },
+    "low":      {
+        "avg":  3.3,
+        "std":  4.5
+    },
+    "precip":   {
+        "avg":  525.0 / 65,
+        "std":  10,
+        "chc":  65.0 / 365
+    }
+}}